算法导论 练习题 15.4-3

#include <stdio.h>#include <stdlib.h>#include <string.h>int lcsLength(int **c,char *x,char *y,int i,int j){if(i<0 || j<0)return -1;if(c[i][j] != -1)return c[i][j];if(x[i-1]==y[j-1]){int a=lcsLength(c,x,y,i-1,j-1);c[i][j]=a+1;}else{int up=lcsLength(c,x,y,i-1,j);int left=lcsLength(c,x,y,i,j-1);if(up>=left)c[i][j]=up;elsec[i][j]=left;}return c[i][j];}int** initC(char *x,char *y){int xlen=strlen(x);int ylen=strlen(y);int **c=(int**)malloc((xlen+1)*sizeof(int*));for(int i=0;i<xlen+1;i++){c[i]=(int*)malloc((ylen+1)*sizeof(int));}for(int i=0;i<xlen+1;i++)for(int j=0;j<ylen+1;j++)c[i][j]=-1;for(int i=0;i<xlen+1;i++)c[i][0]=0;for(int j=0;j<ylen+1;j++)c[0][j]=0;return c;}void printLCS(int **c,char *x,char *y)  {      int xlen=strlen(x);      int ylen=strlen(y);      int i=xlen,j=ylen;      char *s=(char*)malloc((xlen)*sizeof(char));      while(i>=1 && j>=1)      {          if(x[i-1]==y[j-1])          {              s[i-1]=x[i-1];              i--;              j--;          }          else if(c[i][j]==c[i-1][j])          {              s[i-1]='*';              i--;                      }          else              j--;      }      for(;i<xlen;i++)      {          if(s[i]!='*')              printf("%c ",s[i]);      }  printf("\n");} void printC(int **c,int xlen,int ylen){for(int i=1;i<xlen+1;i++){for(int j=1;j<ylen+1;j++){if(c[i][j]==-1)printf("%d ",c[i][j]);elseprintf("%d  ",c[i][j]);}printf("\n");}}void main(){char *x="ABCBDAB";char *y="BDCABA";int **c=initC(x,y);lcsLength(c,x,y,strlen(x),strlen(y));printLCS(c,x,y);//printC(c,strlen(x),strlen(y));getchar();}